The alloy family Hg.sub.1-x Cd.sub.x Te has been used in infrared detection, the choice of the Cd fraction x allowing the choice of the infrared range. Both photoconductive and photovoltaic modes of detection have been used. Work has centered on growth by molecular beam epitaxy (MBE) and by metal-organic chemical vapor deposition (MOCVD). The compound has been grown on substrates of CdTe or lattice matched Cd.sub.1-y Zn.sub.y Te. X-ray analysis however, has shown the existence of a damage layer presumably associated with lattice mismatch at the growth interface when CdTe is the substrate. Similar, but weaker, damage is expected on (Cd,Zn)Te substrates, because composition control in available material is poor.
Recent studies have shown strong electrical activity near the growth interface of (Hg,Cd)Te grown by MBE on CdTe.
17 3 in Large donor and trap densities of greater than 10.sup.17 /cm.sup.3 in roughly 300 angstroms have been inferred. Such properties must cause rapid recombination of photo-generated carriers near the interface, and degrade infrared response.